The present invention relates to a plant for pressure casting sanitary articles such as water closet pans and bidets with an open or closed rinsing rim, which uses moulds of synthetic material.
More particularly, the present invention relates to a pressure casting plant for sanitary articles with several moulds arranged one next to another, each provided at least with one mould lower element, two mould lateral elements, and at least one mould upper element and/or at least one mould transverse element, this or these being positioned transverse to the longitudinal direction of the moulds arranged in a row.
Specifically, the moulds are arranged in a row with their mould lateral elements aligned, and which can be clamped in the alignment direction by two lateral cylinders, to hence form a mould group.
A plant of this type is described in the document EP-B1-0 557 995. In the pressure casting plant described in that document, mould-carrier carriage pairs are provided together with a clamping device for joining the mould elements together by clamping them.
The clamping device is positioned on a clamping frame separated from the mould-carrier carriage.
The clamping frame can be raised and lowered between an operating position and a parking position.
In a plant with at least 6 moulds, three respective pressure casting moulds are ready in the clamping frame to be put into operation. This means that three moulds are ready and clamped, and three products are cast.
The clamping frame, which can be orientated upwards and downwards about a positionable axis relative to the mould element guide, is then orientated upwards and the moulds together with the moulded products are withdrawn by a lifting device and placed on the resting surface.
In this case sixteen clamping devices are required for three moulds, and have to be slackened to withdraw the three formed products.
When the first three forms have been removed from the clamping frame and placed on the resting surface, the clamping frame is returned to its operating position to enclose the next mould elements to be prepared and clamped, and to cast three formed products which are turned and laid on a resting surface after the sixteen clamping devices have been released.
The document EP-0 569 855 describes a plant and process for pressure casting ceramic articles such as water closet bowls.
This plant comprises a longitudinal guide following an axial direction, and several moulds which can be moved along said guide and are provided respectively with at least two lateral elements, a base element, and at least one transverse element which can be moved transversely to the axial direction between the lateral elements, plus an axial clamping device.
The moulds are combined with a single clamping cage comprising transverse clamping devices to hold the mould lower element, the mould transverse element or elements and the lateral elements of each mould together.
Suitable means join the mould transverse elements to the relative transverse clamping devices.
The clamping cage is provided with one clamping frame for each mould, on which four transverse clamping devices are positioned, namely an upper, a rear, a lower and a front.
The front device is fixed on a side which can be moved vertically on the relative clamping frame, and raised and lowered. The clamping frame can be positioned in a return position for withdrawing the formed product and also in a parking position transverse to the axial direction. When the mould elements have been moved apart, the formed product is withdrawn by an extraction device of known construction, which grips it.
The two aforedescribed plants have a certain number of disadvantages.
In the case of the plant of EP-0 569 855, each mould is located in a clamping frame within a single clamping cage. These devices are equipped for simple clamping and slackening of the individual moulds. Each clamping frame is provided with 4 transverse clamping devices which have to be slackened during the extraction of the formed products to enable them to be withdrawn by a special gripper.
In the case of the plant described in EP-B1-0 557 995, the upper and mould lower element of the three moulds are respectively extracted, then the moulds with the formed products within them are rotated about a horizontal axis, and are laid on a parking surface.
The lateral moulds are then loosened to release the formed products, the mould elements are again brought together, and are then re-rotated within the plant.
Hence a number of different clamping devices located within the clamping frame and clamping cage have to be successively slackened and tightened during various processing stages for three moulds respectively.